On December 12, 1891, the Lighthouse Board issued a "Notice to Mariners" informing them that a long sought steam-powered fog signal, featuring two 10-inch whistles similar to those then used on locomotives, had been installed at Point Betsie. This 22 by 40-foot building, utilizing corrugated iron siding and roofing and smooth iron lining, contained two sets of boilers and machinery to protect against an equipment breakdown. The building's current exterior is replicate, while the interior walls are original.
The boilers were wood and coal-fired until the early 1920s, when electricity reached Point Betsie and the equipment was replaced with a more powerful compressor-driven diaphone. Mariners guiding their ships through thick fogs welcomed the greater protection provided by nearly instantaneous two-toned sound blasts every 30 seconds. Doubtless, the change also made life somewhat less burdensome for the light station's three-man crew.
Another important technological innovation came to this building in the mid-1920s, when a radiobeacon was installed, utilizing two tall antenna towers erected immediately north of the building. Concrete blocks still visible at the northwest corner served as the base for the west tower.
Advancing navigational technological gradually rendered the diaphone and radio beacon obsolete, and most
of the equipment was removed from the building in the mid-1970s.